Set Mattermost docker-compose at the right place

pica-mattermost/docker-compose.yml

+version : "2.4"
+  networks:
+    docker_default:
+      external: true
+      name: "docker_default"
+
+volumes:
+  mattermost-config:
+    external: true
+  mattermost-data:
+    external: true
+  mattermost-plugins:
+    external: true
+  mattermost-db:
+    external: true
+
+services:
+  mattermost:
+    image: registry.picasoft.net/pica-mattermost:5.18.0
+    container_name: mattermost-app
+    links:
+      - mattermost-db:mattermost-db
+    volumes:
+      - mattermost-config:/mattermost/config
+      - mattermost-data:/mattermost/data
+      - mattermost-plugins:/mattermost/plugins
+      - /etc/localtime:/etc/localtime:ro
+    environment:
+      - DB_HOST=mattermost-db
+    env_file: ./secrets/mattermost-db.secrets
+    labels:
+      - "traefik.frontend.rule=Host:team.picasoft.net"
+      - "traefik.port=8000"
+      - "traefik.frontend.passHostHeader=true"
+      - "traefik.enable=true"
+    restart: unless-stopped
+
+  mattermost-db:
+    image: postgres:9.4-alpine
+    container_name: mattermost-db
+    volumes:
+      - mattermost-db:/var/lib/postgresql/data
+      - /etc/localtime:/etc/localtime:ro
+    env_file: ./secrets/mattermost-db.secrets
+    restart: unless-stopped